Process for the preparation of hydrocarbon wax compositions comprising deoiling a blend of slack and soft waxes



Dec. 1, 1959 PROCESS FOR THE PREPARATI OLSON ON OF HYDROCARBON WAX COMPOSITIONS Filed Sept. 11, 1957 AROMATICS SOLVENT CUT A 2 3 5 HEATERCHILLER WAXY cum SEPARATOR A :9

on. 8 v

- PUMP cum 4 DISTILLATION A o A m c R M T s OLUMN ,7 FILTER lo SOLVENTRECOVERY DEWAXED on.

T0 STORAGE SLACK wAx HEATER CHILLER I '9 V, V/ SLACK WAX A8 SOLVENT SOFTRECOVERY SOFT wAx wAx MICROCRYSTALLINE LENDER 0R SOLVENT PARAFFIN WAXRECOVERY 40 SOLVENT RECOVERY HEATER DUCTILE 2| CHILLER 25 FILTER 0R LOWF 23 SOLVENT E TEMPERATURE 22 v v' 24 RECOVERY wAx INVENTOR= HIS AGENTROBERT J. OLS N United States Patent PROCESS FOR THE PREPARATION OFHYDRO- CARBON WAX COMPOSITIONS COMPRISING DEOILING A. BLEND OF SLACK ANDSOFT WAXES Robert J. Olson, Houston, Tex., assignor to Shell DevelopmentCompany, New York, N.Y., a corporation of Delaware Application September11, 1957, Serial No. 683,249

5 Claims. (Cl. 20831) This invention relates to the art of preparinghydrocarbon wax compositions. More particularly, it pertains to thepreparation and recovery of hydrocarbon petroleum waxes showing improvedductility, flexibility and low temperature resistance to shock chilling.Still more specifically, it pertains to the preparation of such waxes bythe inclusion of certain soft waxes normally eliminated during thedewaxing processes previously known in the art.

Various methods have been used and suggested for the recovery ofparaflin waxes and microcrystalline waxes from mineral oil distillatesand residues. Thus, it is known to dewax waxy mineral oils or fractionsthereof by cooling, usually after addition of a solvent and/or diluent.Dependent upon the nature of the oil and the conditions of theoperation, such as the lowest cooling temperature, rate of cooling,manner of cooling, etc., the waxes so obtained have certain shortcomingswhich it would be desirable to correct. Certain steps in this directionhave been taken by the recovery of soft wax components in the soft waxfraction usually rejected during a deoiling step.

The separate deoiling of the soft wax fraction is normally attended bydifiiculties due, for example, to the low melting point of the waxesinvolved and to the relatively low wax content inthe soft wax fraction.Because of this, it has been found that the wax cake produced during thedewaxing of a soft wax fraction is prone to crack and thereby presentincreased difficulties in washing out the oil from which it should beseparated. Thus, deoiled soft waxes produced by previously known methodsnormally contain unduly great proportions of oil which cause adegradation in the quality of the wax. Moreover, during the deoiling ofa soft wax by previously known methods, a number of the most desirabletypes of highly ductile low melting soft waxes are eliminated in theoil-containing solvent solution. Thus, the fractions which might be ofgreatest aid in increasing the ductility and low temperaturecharacteristics of waxes are lost. Moreover, the soft wax fraction, dueto ditficulty in satisfactory dewaxing thereof is normally sent tocracking or otherwise disposed of under such circumstances that itsrated dollar value is extremely low as compared to commercial gradehydrocarbon waxes. Hence, any process which results in a usable recoveryof soft waxes otherwise sent to cracking or otherwise disposed ofresults in a corresponding increment in the value of the dewaxingprocess.

In the deoiling of slack waxes steps have previously been taken toincorporate insofar as possible soft wax fractions by lowering thetemperature of deoiling to such a point that the soft waxes crystallizewith the higher ICC melting point wax fractions. While it is thuspossible to segregate a certain proportion of the soft Waxes, the use ofthe low deoiling temperature also causes an increase in the viscosity ofthe oil from which the waxes must be separated. Because of this increasein viscosity the oil tends to be retained upon the surfaces of the waxcrystals and thus the product so obtained is often found to have toogreat a proportion of oil present. Moreover, it will be seen that if thelow temperature deoiling of slack waxes is utilized as a method forretaining insofar as possible the soft waxes normally disposed of in thefiltrate of a deoiling operation, the result is limited by theproportion of soft waxes naturally occurring in the Waxy oil stock beingtreated. Hence, if the proportion of soft waxes is either unduly high orunduly low it will be found that the resulting mixture of hydrocarbonwaxes will not meet specifications set out by users of the Waxes such asmilk carton manufacturers, paper coating manufacturers and the like.

Another disadvantage of the separate deoiling of soft Waxes (in order tobe independent of this fixed naturally occurring ratio of soft waxes toother waxes) comprises the necessity for maintaining a multiplicity ofstorage facilities for the segregation of the various stocks.

It is an object of the present invention to improve the processes forthe preparation of wax compositions. It is another object of thisinvention to improve the low temperature properties of hydrocarbonwaxes. It is a particular object of the present invention to provide aprocess for the preparation of wax compositions exhibiting improvedresistance to cracking upon shock chilling. It is another particularobject of this invention to provide a process for the improvement inductility of microcrystalline waxes. Other objects will become apparentduring the following discussion.

Now in accordance with this invention, it has been found that improvedwax properties, especially at low temperatures, may be obtained byincluding in the wax compositions wax components in essentially the sameboiling range as ordinary paraffin waxes or microcrystalline waxespresent in the compositions but which are normally lost in deoilingoperation. More particularly, an improved process for the preparation ofwax compositions having improved flexibility, ductility and resistanceto cracking upon shock chilling comprises dewaxing a waxy petroleum oilto obtain a slack wax, deoiling the latter to obtain a deoiled wax and asoft wax, combining the soft wax with further proportions of the sameslack wax and deoiling the combined mixture of waxes.

The foregoing objects and others as well as the process of the presentinvention will be better understood by reference to the accompanyingdrawing wherein Fig. 1 is a typical arrangement of apparatus forcarrying out the process of the present invention in preparing animproved paraflin wax composition.

Referring now to Fig. 1, a waxy oil contained in a storage tank 1 isconveyed to a distillation column 2 wherein the oil is separated infractions according to boiling point ranges, one of which may bedesignated cut A. This is conveyed by means of line 3, being pumped bypump 4 to a point where it is mixed with a selective solvent foraromatics coming from storage tank 5. The mixture is passed to aseparator 6 wherein a solution of the aromatics is separated andremoved, the waxy rafiiuate being mixed with a dewaxing solvent from thesolvent recovery tank 7 and passed to a heater chiller 9 where waxespresent in the mixture are crystallized.

The wax-solvent-oil mixture is passed to a filter 10 for the separationof the waxes from the remaining components of the mixture. The filtratecomprises a dewaxed oil dissolved in a solvent which is then passed to asolvent recovery system 7 from which a dewaxed oil is passed to storage.The slack wax remaining on the filter comprises a mixture of the waxespresent in the waxy oil contaminated by 260% by Weight of oil. Thismixture is conveyed by pump 11 to a point in line 12 where it is mixedwith a deoiling solvent from a solvent recovery system 13 and thenpassed to a heater 14 to dissolve the slack wax in solvent. Thereafter,it is passed to chiller 15 for precipitation of wax and the wax soprecipitated is recovered on the filter in filter 16.

The filtrate from filter 16 comprises a solution of a soft wax containedin the solvent. This solution is passed by means of pump 17 to thesolvent recovery system 13 wherein the solvent is separated from thesoft wax. The soft wax is then passed by means of line 18 to a blender19 wherein it is blended in suitable proportions with furtherproportions of slack wax from the filter 10. Ordinarily the proportionsof the blended materials will be 3-5 volumes of the slack wax and 1-5volumes of the soft wax. Solvent-from the solvent recovery 13 orelsewhere is then added to the blend which is transmitted by means ofline 20 to the heater 21 wherein the slack wax-soft wax blend issubstantially completely dissolved in a deoiling solvent and passed bymeans of line 22 to a chiller 23 wherein the mixture of waxes and softWaxes are precipitated from any oil present, the oil being dissolved insolvent. The mixture is passed through line 24 to the filter 25 toremove the precipitated waxes, the solution of oil and solvent beingsent to solvent recovery system 26. Traces of solvent are removed fromthe filtered and separated waxes in the solvent recovery system 27, thusresulting in the production of a wax having improved low temperatureproperties or, in the case of microcrystalline waxes particularly,improved ductile properties.

In the case of microcrystalline wax compositions especially, it may bedesirable to process this particular wax product still further such asby a high temperature Wax sweating or high temperature solvent deoilingoperation to obtain a relatively high melting hard wax on one hand and amore ductile adhesive microcrystalline wax composition on the other.Applying the system of apparatus illustrated in Fig. 1 to the processingof microcrystalline wax compositions it will be understood that themicrocrystalline waxes normally occur in residual oils and hence, wouldbe derived from a point at the lower end of the distillation column 2rather than from one of the distillate cuts, namely, cuts A or Bindicated on distillation column 2.

By the above description, it can be seen that the principal object ofthe present invention is to incorporate soft waxes normally lost in thefiltrate from filter 16 of Fig. 1. The same object cannot beaccomplished to nearly the same extent by sending the soft waxes back toa point in the apparatus prior to the preparation of the slack wax sincethese soft wax fractions then would be removed in large part in thedewaxed oil, thus, undesirably raising the pour point of the oil andpreventing utilization of the soft waxes in the wax compositions wherethey are desirable. While the conditions well known in the art fordewaxing may be employed, it is preferred that relatively low dewaxingtemperatures be utilized. However, the benefits of the present inventionare also obtained when ordinary dewaxing temperatures are present.

The waxy petroleum oils which may be treated according to the process ofthe present invention comprise 2,915,450 Y e e either distillatepetroleum fractions, particularly the distillate lubricating oilfractions, as well as residual oils such as short residues and the like.It is well known that the paraffin waxes exist largely in the distillatefractions (with the exception of the high melting point paraffins whichmay be present in the residues), while the microcrystalline waxes arenormally found in the residual oils either alone or in combination withany melting point parafiins which may be present. The proportions ofwaxes in these fractions are well known in the art. The major componentsof the present compositions insofar as they are paraffin wax-containingpetroleum oils comprise normal, iso-paraffin and cycloparafiinhydrocarbon waxes having individual melting points within the usualrange from about l10165 F., more normally between about -145 F. Thedistillate paraffin waxes usually predominate in normal paraflins andmay comprise a single wax but ordinarily will be a mixture of relativelyclosely related paraffin waxes. The general practice is to distill abroad lubricating oil fraction which may be dearomatized either prior toor subsequent to redistillation for the preparation of relatively narrowboiling range waxy oil cuts.

The residual oils normally comprise what is known as bright stock whichis a high viscosity residual lubricating oil combined together withmicrocrystalline waxes, any high melting point paratfin Waxes which mayoccur and, if a mixed base crude is being treated, asphaltic fractions.Asphalts may be removed by propane extraction or by other means prior todewaxing operations.

The initial dewaxing operation is by means of selective solvents whichare well known in the art. In carrying out the improved process of thepresent invention, the dewaxing and deoiling operations are accomplishedby chilling the Waxy oils together with oil solvents or diluentsincluding, for example, ketones of less than about 8 carbon atoms permolecule such as acetone, methylethyl ketone, methyl propyl ketone,methyl isobutyl ketone, etc.; alcohols having less than about 8 carbonatoms per molecule such as ethyl alcohol, isopropyl alcohol, normalpropyl alcohol and the like. Petroleum naphthas, halogenatedhydrocarbons, such as ethylene dichloride and dichloroethylene;hydrocarbons having less than about 8 carbon atoms per molecule such asbenzene, toluene, ethane, ethylene, propane, propylene, butane,isobutane, etc. Mixtures of solvents or diluents such as benzenetogether with methyl ethyl ketone may be employed as disclosed in priorart dewaxing processes.

Solvent dewaxing and deoiling may be carried out at temperatures whichare well known and with proportions of solvent to waxy oil or oily waxwhich are known in the art. Dewaxing temperatures when using polarsolvents are usually in the range from about l5 F. to +15 F., thedewaxing solvents (polar or non-polar) being present in amounts fromabout 1 volume to 5 volumes per volume of waxy oil. The dewaxingtemperature range when utilizing lower molecular weight alkanes only(e.g. propane) are usually between about 40 F. to about 0 F. Dewaxingusually results in the formation of a dewaxed oil and a slack wax, thelatter term being applied to the wax product contaminated with a greateror lesser amount of oil or oil-like constituents. The slack wax normallycontains from about 2 to about 60% by weight of oil but this figure mayvary broadly. In deoiling operations the proportion of solvent isnormally increased to between about 2 and 7 volumes of solvent pervolume of oily wax, deoiling temperatures being usually between about 32F. and 65 F.

The soft wax fractions are normally eliminated in the filtrate from thedeoiling of slack waxes insofar as they apply to distillate waxproduction.

The soft waxes comprise mixtures of highly branched or naphthenic waxeshaving substantially lower melting points and other more plasticproperties than those of the more nearly straight chain waxes of thesame molecule weight. Consequently, within a given narrow boiling rangethere may be high melting waxes which are typical paraffin waxes as wellas low melting waxes which approach the subject wax fractions normallyeliminated as the filtrate from the deoiling of a slack Wax.Consequently, the boiling range of the waxes in the soft wax fractionare roughly co-extensive with the boiling range of the parafiin waxes ormicrocrystalline waxes naturally existing within the same petroleum oilfraction being processed.

The soft wax members can best be described by reference to a particularexample wherein the soft waxes were deoiled to obtain what may bereferred to as plastic wax. A waxy lubricating oil distillate boilingwithin the range from about 650 F. to about 950 F. (at atmosphericpressure) is subjected to solvent dewaxing by means of known selectivedewaxing solvents. Preferably this comprises the combination of a lowmolecular weight aliphatic ketone and an aromatic hydrocarbon such asbenzene or toluene in volume proportions of 3:1 to 1:3 (preferably 2:1to 1:2). More specifically, a preferred pair of dewaxing solventscomprises methyl ethyl ketone and toluene in proportions of betweenabout 2:1 to 1:2 by volume. A suflicient amount of the de waxing solventis employed to completely dissolve the waxy lubricating oil attemperatures in excess of about 120 F after which the solution is cooledto a dewaxing temperature, preferably in the order of between about to+15 F. when using polar solvents or -40 F. to 0 F. for lower alkanedewaxing solvents. At about the dewaxing temperature, the slack wax isfiltered or centrifuged from the dewaxed oil. The slack wax is in turnsubjected to a solvent deoiling procedure, preferably using the sametype of deoiling solvents. The slack wax is dissolved in the solvents,preferably methyl ethyl ketone mixed with toluene usually at an elevatedsolution temperature and cooled to a temperature between about 35 F. andabout 50 F., at which point the refined paraffin wax is filtered. Thisparaflin wax is treated in accordance with known procedures, such as byrepulping or washing on a filter in order to obtain a fully refinedparaflin wax having a melting point between about 135 and about 145 F.

The soft wax mixture left in solution in the solvent is in turnsubjected to a deoiling treatment either by cooling the existingsolution down to a point where the plastic waxes crystallize or byremoving a sufficient amount of the solvent to provide a moreconcentrated solution of the soft wax, so that more easily attaineddeoiling temperatures may be employed. Preferably, the soft wax isdissolved in between about 2 and about 6 parts by volume of deoilingsolvent per part of soft wax, heated .to a temperature in the order ofll60 F., and cooled to a temperature between about and 40 F., at whichpoint the plastic waxes separate and are removed by mechanicalseparation such as by centrifuging or filtration. In order to remove themaximum amount of contaminating oil from the precipitated waxes, it is apreferred practice to subject the waxes so obtained to washing orrepulping or both within the filtration temperature range in order toobtain the desired plastic wax.

The product so obtained has unique properties not found in any waxdescribed in the prior art. It has a melting point within the range fromabout 108 to about 117 F., a viscosity between about and 45 SSU at 210F., a refractive index at 70 C., between about 1.4365 and 1.4500 and anoil content, as determined by the standard ASTM method, of less thanabout 0.5%. The penetration of the wax at 77 F. is between about and 80mm./ 10 by ASTM Method D1321-54T.

It will be understood that this constitutes a single example of theplastic waxes to be obtained from the soft waxes rejected in thedeoiling of slack wax. It will also be understood that theseplasticwaxes are not isolated per se in the process of the present inventionbut are recycled for combination with further proportions of slack waxfrom the same petroleum oil out after which the combination of slack waxand soft wax is then deoiled to obtain the wax compositions found tohave superior ductility, flexibility and resistance to low temperatureshock chilling.

In order to illustrate the process of the present invention thefollowing examples are presented but it will be understood that theinvention is not to be limited thereto. In these comparative tests aslack wax was utilized which had been obtained from the dewaxing of anintermediate boiling lubricating oil distillate (from a Texas crude oil)which had been solvent extracted prior to dewaxing operations. The slackwax contained about 8% by weight of oil. In the operation utilized forthe comparative testing, the slack wax was subjected to a dewaxingoperation using a mixture of methyl ethyl ketone and toluene, thedewaxing temperatures being either 35 F. or 15 F., as indicated in Table1 which follows. The combination of soft wax so derived when mixed withfurther proportions of the same slack wax in varying ratios as definedin Table 1 resulted in the production of waxes having improved lowtemperature properties, also, as indicated in the table.

Sample A represents the process of deoiling a slack wax from anintermediate boiling range lubricating oil out wax at an ordinarytemperature (35 F.), yielding a 139.5 F. melting point wax which isrelatively hard, relatively inflexible, and tends to crack excessivelywhen shock chilled by cold liquids. The latter property in particularmakes this wax unsuitable for coating cardboard containers intended tobe filled with cold liquids, as for example, milk.

Deoiling the same slack wax at a relatively low temperature (sample B)yields a product wax which is somewhat softer, more flexible andimproved in low temperature fracture resistance properties as comparedto the product from sample A. However, the improvement in theseproperties is limited.

The process of this invention is illustrated in its preferred form bydeoiling runs resulting in samples C, D and E. In those experiments 1,3, and 5 parts of soft wax were added to 4 parts of slack wax and thecombination deoiled at a relatively low deoiling temperature (15 F.).The product waxes were relatively soft paraffin waxes showing increasedflexibility and little or no cracking in the low temperature fracturetest. The product wax would be useful in applications where increasedflexibility is advantageous, i.e. in coated bread wrappers or as acoating for frozen food wrappers. It would also be useful as a coatingfor cardboard cartons to be used for holding cold liquids such as milkor other beverages.

The process is not limited to low deoiling temperatures but is alsoapplicable at ordinary deoiling temperatures, such as 35 F. Deoilingruns producing samples A, F, G and H show how the process is effectiveat a deoiling temperature of 35 F. As the proportion of soft wax in thefeed to deoiling increases from 0 to 1 to 3 to 5 parts of soft wax per 4parts of slack wax, the product wax from the deoiling operationsdecrease in melting point and hardness, increases somewhat inflexibility and shows improved low temperature fracture resistance.

This principle, of adding a soft wax back to a slack Wax of the sameboiling range, and deoiling the combination together, is applicable tothe manufacture of flexible waxes from streams other than theintermediate boiling range stock illustrated here. For example, it isapplicable to the lower boiling wax distillate stream where it isdesirable to produce a wax having an increased concentration of lowmelting components. It is applicable to the high boiling distillatestream to produce higher melting point, flexible waxes. It also isapplicable to the residual stream, to produce microcrystalline waxes ofgreater ductility and improved sealing quality.

TABLE 1 Samnle A B C D E F G H Charge Stock Composition:

Slack Wax, Parts 1 1 4 4 4 4 4 4 Soft Wax, Parts 0 1 3 1 3 5 CongcalingPoint, F, ASTM D938 131 131 128 124 120 128 124 120 Oil Content Tercentw. ASTM D721 8 8 18 17 21 Laboratory Deoiling Conditions N grmal LprwLol w La w L ri w N rli rmal N tl rmal Ng rmal 9111 em em m m Solvent,MEX/Toluene. 50/50 50/5) 50/50 50/5 0 50250 Primary Dilution Ratio 4 4 44 4 4 4 4 Secondary Dilution Rati 2 2 2 2 2 2 2 2 RecrystallizationFilter Feed Temp, 111. 35 15 15 15 15 35 35 35 Recrystallization WashRatio 3 3 3 3 3 3 3 3 Repulp Dilution Ratio a 3 3 3 3 3 3 3 RcpulpFilter Feed Temp, F. 35 15 15 15 15 35 35 35 Repulp Wash Ratio 2. 5 2. 52. 5 2. 5 2. 5 2. 5 2. 5 2. 5 Yield, Percent w.:

Cake 76.8 85.2 74. 3 68. s 68.6 68. 5 57. 7 55. 5 Properties of ProductWax:

Melting Point, F., ASIM D87 139. 5 136.5 135. 3 131.0 127.8 137. a 134.5 131.8 011 Content, Percent w., ASTM D721 Nil 0.1 0.1 0.4 0.4 Nil Nil0.1 Hardness, Needle Penetration at 77 mm./10 ASTM D1321 11 13 15 21 1315 19 Flexibility at 73 F., Angle o Degrees 8 12 17 23 33 16 17 17 LowTemperature Fracture Resistance,

Inches of Cracks 35 25 4. 5 6 lone 2. 5 0. 5

Tests utilized in obtaining the data given in Table l 25 istics whichcomprises distilling a waxy lubricating oil above may be described asfollows: into a plurality of waxy lubricating oil fractions, solvent L II extracting a fraction having a boiling range between about 0wtemperature fracture reszstance test 0 R and F at 760 mm Hg pressureSolvent Five (5) ml. of molten wax at 230 F. is placed in dcwaxing theextracted fraction to produce a slack wax, an unwaxed quart milk cartonbottom, allowed to solidify 30 solvent deoiling said slack wax toproduce a substantially and the waxed carton bottom conditioned for onehour deoiled paraffin wax and an oil-containing soft wax, at 73 F. and50% relative humidity. The waxed car- Combining 3 t0 5 Volumes offurther Portions fi ton bottom is then shock chilled byimmersion in F.same l k w wi 1 to 5 m s f the oll-contalmns water for one minute, whichtends to induce the forma- 9 f and deoiling the mixture to obtain asubstantion of cracks. The number of inches of cracks is de- 35 yOil-free 60111130519011 havlng P 10W termined by measurement with a mapmileage gauge. A temperature P p the Wax COmPOYIFmS of said d wax Showsli l or no ki i hi test position derived from the further portions ofthe slack wax having a boiling range substantially coextensive Wax fl ytest with the wax components of the composition derived A specimen ofwax 2 inches x 0.5 inch x 0.020 inch from the Soft is cut from a sheetof wax which had been prepared T Process of Waxy lubncatmg 011previously by solidification on water. The specimen is Stock f dewaxcdlubflcatmg 011 components of 9 conditioned at test temperature for onehour, then mount- P Pomt and Substamlany Parafiin Wax ed in theflexibility testing instrument. The flexibility Improved 10WtemPHamIePIOWFtWS Whlch compnses tester consists of two parts, one, apair of rotatable jaws the Slap? of solvent dewaxmg Bald Stock toProduce a in which one end of the wax specimen is fastened and,sltbstanuauy Wax free 011 and a slack solvent two, a fixed arm toprevent movement of the opposite 011mg f Wax to a Parafiin Wax and anend of the wax specimen in the direction of rotation oll'comemmg softcombmmg 3-5 volumes of the when the jaws are rotated one end at thespecimen is latter with 4 volumes of the same slack wax and solventmounted in the jaws and the jaws rotated to bring the fieolhng themlxmre whereby a cpmposmor} having opposite end of the Specimen to justtouch the fixed improved low temperature characteristics is obtained,the arm. This position is considered the zero point. The f Waxcomponents. Present .composmon havmg a jaws are then rotated at a rateof 0 per minute caus boiling range only w1th1n the boilmg range of theslack ing the wax specimen to bend. The angle at which the Th f specimencracks is measured by means of a protractor e Proms? Segregatmg aSubstantially fee fastened to the jaws. The results of tests on fivespeci- P i f havmg.1mprqv.d.l0W temperature mens are averaged andreported as the angle of fracture. i Whlch .compnses d1sun mg. aluiancatmg 011 I claim as my invention: into a plurality of waxylubrlcatmg oil fractions, solvent L The process of segregating aSubstantially oiHree extracting one of said fractions solvent dewaxingthe expetroleum wax having improved properties which comtracted fractlonto produce .fi t w 011 prises the steps of solvent dewaxing a waxypetroleum oil a a g g Solvent deolhng sald slack ph stock to produce asubstantially wax-free oil and a slack uce 2? parafiinlwax and an t i iwax, solvent deoiling a portion of the slack wax to sep- Pg i 3-5 v0 ofthe Oll'contammg 9 t arate a substantially oil-free petroleum wax froman oily i wlt .volumes of the Same Slack wax and i i soft wax, combiningthe oily soft wax with 3-5 volumes t e mixture whereby paraffin of thesame slack wax and solvent deoiling the mixture, haymg Improvedtemperature characterisilcs 15 Ohwhereby a wax composition havingimproved properties t the FPmPOsltlOn so phepfired conigimmg waxes isobtained, the soft wax components of the composition q bolhng range onlyWlthlfl I116 oiling range of having a boiling range substantially withinthe boiling t e S ac range of the slack wax components of thecomposition.

2. A process according to claim 1 wherein the waxy petroleum oil stockis a residual oil containing microcrystalline waxes.

3'. The process of segregating a substantially oil-free parafiin waxhaving improved low temperature character- References Cited in the fileof this patent UNITED STATES PATENTS 2,248,668 Gee July 8 1941 2,670,318Halamka et a1. Feb. 23, 1954 2,761,814 Post Sept. 4, 1956

1. THE PROCESS OF SEGREGATING A SUBSTANTIALLY OIL-FREE PETROLEUM WAXHAVING IMPROVED PROPERTIES WHICH COMPRISES THE STEPS OF SOLVENT DEWAXINGA WAXY PETROLEUM OIL STOCK TO PRODUCE A SUBSTANTIALLY WAX-FREE OIL AND ASLACK WAX, SOLVENT DEOILING A PORTION OF THE SLACK WAX TO SEPARATE ASUBSTANTIALLY OIL-FREE PETROLEUM WAX FROM AN OILY SOFT WAX, COMBININGTHE OILY SOFT WAX WITH 3-5 VOLUMES